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/*************************************************************************
* Copyright (c) 2016-2019, NVIDIA CORPORATION. All rights reserved.
*
* See LICENSE.txt for license information
************************************************************************/
#include "core.h"
#include "topo.h"
#define BUSID_SIZE (sizeof("0000:00:00.0"))
#define BUSID_REDUCED_SIZE (sizeof("0000:00"))
ncclResult_t getCudaPath(int cudaDev, char** path) {
char busId[BUSID_SIZE];
CUDACHECK(cudaDeviceGetPCIBusId(busId, BUSID_SIZE, cudaDev));
for (int i=0; i<BUSID_SIZE; i++) busId[i] = tolower(busId[i]);
char busPath[] = "/sys/class/pci_bus/0000:00/../../0000:00:00.0";
memcpy(busPath+sizeof("/sys/class/pci_bus/")-1, busId, BUSID_REDUCED_SIZE-1);
memcpy(busPath+sizeof("/sys/class/pci_bus/0000:00/../../")-1, busId, BUSID_SIZE-1);
*path = realpath(busPath, NULL);
if (*path == NULL) {
WARN("Could not find real path of %s", busPath);
return ncclSystemError;
}
return ncclSuccess;
}
const char* pathDists[] = { "PIX", "PXB", "PHB", "NODE", "SYS" };
int pciDistance(char* path1, char* path2) {
int score = 0;
int depth = 0;
int same = 1;
for (int i=0; i<strlen(path1); i++) {
if (path1[i] != path2[i]) same = 0;
if (path1[i] == '/') {
depth++;
if (same == 1) score++;
}
}
if (score <= 3) {
/* Split the former PATH_SOC distance into PATH_NODE and PATH_SYS based on numaId */
int numaId1 = getNumaId(path1);
int numaId2 = getNumaId(path2);
TRACE(NCCL_INIT, "depth %d score %d path1 %s numaId %d path2 %s numaId %d", depth, score, path1, numaId1, path2, numaId2);
return ((numaId1 == numaId2) ? PATH_NODE : PATH_SYS);
}
if (score == 4) return PATH_PHB;
if (score == depth-1) return PATH_PIX;
return PATH_PXB;
}
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